CN102222225B - Finger vein image anti-counterfeiting acquiring method - Google Patents

Abstract

The invention relates to a finger vein image anti-counterfeiting acquiring method. The finger vein image anti-counterfeiting acquiring method is used for judging whether an object to be detected is a real finger of a human body, avoids false detection to foreign maters, forged fingers or images, avoids the problems of different sizes of front ends and rear ends of individual fingers and uneven brightness of the middle section of condyle and condyles, overcomes entire or partial detailed information loss caused by uniform brightness, and also overcomes potential safety hazards that a collection device is cheated by rapidly switching the fingers of the human body into the forged fingers or the images after a detection system is triggered, and is realized by comprehensively executing three methods, namely a finger vein image obtaining method, a human body finger biological characteristic detecting method, and a light source controlling and adjusting method, wherein the light source controlling and adjusting method is most important. The method has advantages of simpleness, convenience and rapidness in operation, use safety and energy saving, is suitable for biological characteristic collecting parts in the human body biology authenticating field, and is easy to popularize as soon as possible.

Description

The false proof acquisition methods of a kind of finger venous image

Technical field

The present invention relates to image acquiring method, the false proof acquisition methods of especially a kind of finger venous image.

Background technology

At present, finger vein identification technology is the new bio recognition technology that recent development is got up, and the characteristic of employing is present in inside of human body, can't duplicate, and depend on live body and exist, and has higher antifalsification.The finger vena base of recognition is obtaining of finger venous image with key.The universals of human finger all are that the comparatively tiny rear end of front end is comparatively thick; The finger interior joint is divided into three sections; Have the slit between the joint, the size of joint own is also different, Different Individual finger size, thickness all variant (some most females fingers vein blood vessel is very tiny).The same light source irradiation down; The light transmission capacity of Different Individual finger is difference to some extent, and same individual finger front and back end light transmission capacity difference to some extent, and joint slit and condyle portions light transmission capacity be difference to some extent also; Problems such as the vein image that obtains integral body possibly occur pointing or partial exposure is not enough, over-exposed, the different parts exposure is inhomogeneous; Cause in the original vein image finger vena detail section or integral body to be lost, picture quality is low, has a strong impact on follow-up feature extraction and identification.The dielectric multiplier of human finger live body is bigger, and frequency greatly between 12～18, just can judge through detecting specific inductive capacity whether measured object is the human finger live body when 100～500kHz.Finger-image acquisition system is in the market often only gathered vein image; Can not judge whether adopted object is human finger; Finger of forging or vein image card also possibly cheated acquisition system and smoothly through identification, made the higher vein identification of safe class originally have potential safety hazard.

A kind of prior art is that September 2, publication number in 2009 are that CN101520840A, denomination of invention are the Chinese patent of " finger vein image acquisition device and method " like the open date, discloses a kind of scheme of adjusting vein image brightness through detection finger venous image central area mean flow rate adjustment shutter; Another kind of prior art is that March 2, publication number in 2011 are CN101982826A, the denomination of invention Chinese patent for " the self-adjusting finger vena collection and recognition method of a kind of light-source brightness " like the open date, and having disclosed a kind of is the scheme of quality adjustment light-source brightness of the rectangular area at center with horizontal axis and vertical axis according to vein image; How yet the technical scheme that this invention provides all not mentioned avoids that individual finger front and back end varies in size if being, the scheme of problem such as brightness irregularities between joint stage casing and joint; The also not mentioned technical scheme that how to improve the vein image contrast can't overcome brightness irregularities and causes integral body or local detailed information to lose problem.Also having a kind of prior art to be January 26 in 2011 for, publication number like the open date is CN101957914A, the denomination of invention Chinese patent for " a kind of finger vein image acquisition device "; Disclose a kind of vital sign detecting unit, gather all processes and carried out twice vital sign detection based on capacitive sensing; Yet this invention only is loosely to propose vital sign to detect; Do not see concrete relevant method of operating explanation, twice limited vital sign detection still can't overcome the human finger of putting into and treat to switch to the potential safety hazard of forging finger or image deception harvester fast after the detection trigger system works.The present invention proposes solution to the problems described above.

In view of the foregoing, finger vein image acquisition device and method need to improve.

Summary of the invention

The objective of the invention is provides a kind of finger venous image false proof acquisition methods in order to overcome deficiency of the prior art, judges whether measured object is real human finger live body, avoids the flase drop to foreign matter, forgery finger or image; Avoided that individual finger front and back end varies in size, the problem of brightness irregularities between joint stage casing and joint, overcome because of brightness irregularities causes integral body or local detailed information and lost; Having overcome human finger treats to switch to the potential safety hazard of forging finger or image deception harvester fast after the detection trigger system works.

The present invention to achieve these goals; Adopt following technical scheme: the false proof acquisition methods of a kind of finger venous image; Be to realize by the comprehensive execution that finger venous image obtains, the human finger biological characteristic detects, light source control is adjusted three kinds of methods; Described finger venous image obtains, and follows these steps to successively carry out:

The S1 system initialization, the wait human finger is put into;

Whether S2 human finger: detect finger and put into, detect human finger and put into;

S3 starts light source, and original intensity is set;

S4 obtains image, motion detection: image is carried out motion detection;

The S5 finger is in place: judge whether finger is in place;

Whether whether S6 human finger: detecting current checked object is human finger;

S7 obtains image, the Adjustment System parameter: to the discrepancy adjustment systematic parameter of tested individuality, parameter regulation means will combine described light source control adjustment member to carry out, and the light source control adjustment process is undertaken by coarse adjustment, fine tuning and three steps of enhancing successively; The concrete steps of coarse adjustment are following: carry out step S711 earlier and obtain image, calculate Bt; Carry out step S712 again and judge Bt ∈ T? Carry out step S713 again and adjust S1, S2, S3 synchronously: the light source S1 that divides into groups, S2 and S3 brightness are adjusted synchronously; Whether carrying out step S714 then, to detect current checked object be human finger; The concrete steps of fine tuning are following: carry out step S721 earlier and obtain image, calculate Bf, Bm, Br; Carry out step S722 again and judge Bf/Bm/Br ∈ Ts? Carry out step S723 adjustment S1, S2, S3 again: the light source S1 that divides into groups, S2 and S3 brightness are adjusted separately; Whether carrying out step S724 then, to detect current checked object be human finger; The concrete steps that strengthen are following: carry out step S731 earlier and obtain also split image, calculate Bv, Bg and Dt; Carry out step S732 again and calculate max (Dt); Carry out step S733 again and judge Bt ∈ Tz? Carry out step S734 synchronous micro-adjusting S1, S2, S3 again: the brightness of synchronous micro-adjusting grouping light source S1, S2 and S3; Whether carrying out step S735 again, to detect current checked object be human finger; Carrying out step S736 then is provided with S1～S3 and produces max (Dt);

Whether whether S8 is human finger: detecting current checked object is human finger;

Whether S9 adjusts end: judge whether that adjustment finishes;

S10 gathers high quality graphic;

S11 closes light source;

S12 withdraws from operation;

Wherein the most important thing is the light source control adjustment; Said finger venous image obtains confirms human finger rapid adjustment parameter in place, automatic, obtains finger venous image; Said human finger biological characteristic detects omnidistance work, can thoroughly get rid of the interference of non-human finger; Said light source control adjustment is pointed size, thickness according to individuality, and the light intensity control information is calculated in the position in finger interior joint size and joint slit, and dynamically adjustment is corresponding to the grouping light source of section before, during and after pointing, to obtain original finger venous image.

Described finger venous image obtains, and light source and image capture device all are not in closed condition when having human detection; Effective in order to ensure testing process in addition, prevent that the detection starting descendant from forging finger or image deception acquisition system for extracting fast to point to change, stop immediately detecting in case find to point to withdraw, withdraw from all operations, further improve the security of system; Follow these steps to successively carry out:

The S1 system initialization, the wait human finger is put into: described initialization mainly is that initialization human finger biological characteristic detects, and frequency is set at 100～500kHz;

Whether S2 human finger: detect finger and put into; Detecting human finger puts into; Downward execution in step S3; Otherwise returning step S2 detects again: described detection finger concrete grammar is to detect to put into to detect to be the dielectric constant values of target, when detecting dielectric constant values between 12～18, promptly confirms it is that human finger is put into;

S3 starts light source, and original intensity is set: the brightness regulation scope E of said light source is provided with as follows: general human body finger detection appropriate brightness is 0.4～0.5E, and initialization brightness is 0.2～0.3E; Said light source is grouping light source S1, S2 and S3, the position correspond respectively to seized finger preceding, in and back segment; Concrete control method adopts PWM dutycycle control mode, and light source control information is respectively C1, C2 and C3, C1/C2/C3 ∈ Tc, and Tc=0～100 are the duty cycle adjustment scope;

S4 obtains image, motion detection: image is carried out motion detection, in order to accelerate detection speed; Described method for testing motion adopts the frame error method to realize; Concrete operations are that as Dpix＞Td, Td=30 is an error thresholds with the consecutive frame calculating respective pixel difference Dpix of image sequence; Pixel motion is counted U=U+1; At last according to following formula:

confirms that finger is in place, and Tm is a motion pixel proportion threshold value, and M * N is a resolution;

S5 finger is in place: judge whether finger is in place, points downward execution in step S7 in place, otherwise execution in step S6: whether condition in place is a motion pixel proportion threshold value to said judgement finger is set to Tm=0.1;

Whether whether S6 human finger: detecting current checked object is human finger; Be then to return step S5 to rejudge finger situation in place, close light source and withdraw from all operations otherwise jump to step S11: this just can effectively get rid of artificial imitation human finger or the image security threat to system;

S7 obtains image, the Adjustment System parameter: to the discrepancy adjustment systematic parameter of tested individuality, parameter regulation means will combine described light source control adjustment member to carry out;

Described light source control adjustment; According to individuality finger size, thickness, the position in finger interior joint size and joint slit is different, calculates the light intensity control information; Dynamically adjustment is corresponding to the grouping light source of section before, during and after pointing, to obtain original finger venous image; Avoided that individual finger front and back end varies in size, the problem of brightness irregularities between joint stage casing and joint, overcome because of brightness irregularities causes integral body or local detailed information and lost; The light source control adjustment process is undertaken by coarse adjustment, fine tuning and three steps of enhancing successively.

Described coarse adjustment comprises step S711, S712, S713 and S714, and grouping light source S1, S2 and S3 brightness are adjusted synchronously: described grouping light source S1, S2 and S3, the position correspond respectively to seized finger preceding, in and back segment; Concrete control method adopts PWM dutycycle control mode, and light source control information is respectively C1, C2 and C3, C1/C2/C3 ∈ Tc, and Tc=0～100 are the duty cycle adjustment scope; According to the brightness average Bt that obtains the image calculation finger venous image, adjust C1, C2 and C3 synchronously and make that

T is a coarse adjustment brightness average threshold value; Concrete method of adjustment is for as

time; T=120～150 are brightness average threshold value, if Bt＞T is C1=C1-1 then, and C2=C2-1; C3=C3-1; If Bt＜T is C1=C1+1 then, C2=C2+1, C3=C3+1; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps of coarse adjustment are following:

S711 obtains image; Calculate Bt: the brightness average of said Bt image; The practical implementation algorithm is a following formula:

wherein p (i j) is the capable j row of i gray values of pixel points in the image;

Does S712 judge Bt ∈ T?: said T=120～150 are brightness average threshold value, if set up then downward execution in step S721, otherwise execution in step S713;

S713 adjusts S1, S2, S3 synchronously: the light source S1 that divides into groups, S2 and S3 brightness are adjusted synchronously; Concrete method of adjustment is that the brilliance control parameter reduces control unit, the then C1=C1-1 of the unit of control as if Bt＞T then whole reduction S1, S2 and S3 brightness; C2=C2-1, C3=C3-1; Improve S1, S2 and S3 brightness if Bt＜T is then whole, the brilliance control parameter increases a control unit, the C1=C1+1 of the unit of control then, C2=C2+1, C3=C3+1; The C1/C2/C3 of the unit of control ∈ Tc wherein, duty cycle adjustment scope Tc=0～100;

Whether S714 detects current checked object is human finger; Be execution in step S711 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11.

Described fine tuning; Comprise step S721, S722, S723 and S724; Adjust separately according to tested finger characteristics grouping light source S1, S2 and S3 brightness: said Bf, Bm and Br be respectively the finger before, in and back segment brightness of image average; The brightness of independent adjustment S1, S2 and S3 is so that Bf ∈ is Ts, Bm ∈ Ts, Br ∈ Ts, and Ts is a fine tuning brightness average threshold value.In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps of fine tuning are following: S721 obtains image; Calculate Bf, Bm, Br: before said Bf, Bm and Br are respectively finger, in and back segment brightness of image average; The practical implementation algorithm is respectively following formula:

wherein p (i j) is the capable j row of i gray values of pixel points in the image;

Does S722 judge Bf/Bm/Br ∈ Ts? Said Ts=125～140 are fine tuning mean flow rate threshold value, if set up then downward execution in step S731, otherwise execution in step S723;

S723 adjustment S1, S2, S3: the light source S1 that divides into groups, S2 and S3 brightness are adjusted separately, and concrete method of adjustment then reduces a control of S1 brightness unit, the control C1=C1-0.2 of unit for as Bf＞Ts; When Bf＜Ts then improves a control of S1 brightness unit, the control C1=C1+0.2 of unit; As Bm＞Ts, then reduce a control of S2 brightness unit, the control C2=C2-0.2 of unit; When Bm＜Ts then improves a control of S2 brightness unit, the control C2=C2+0.2 of unit; As Br＞Ts, then reduce a control of S3 brightness unit, the control C3=C3-0.2 of unit; When Br＜Ts then improves a control of S3 brightness unit, the control C3=C3+0.2 of unit; The C1/C2/C3 of the unit of control ∈ Tc wherein, duty cycle adjustment scope Tc=0～100;

Whether S724 detects current checked object is human finger; Be execution in step S721 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11.

Described enhancing comprises step S731, S732, S733, S734, S735 and S736, grouping light source S1, S2 and S3 brightness synchronous micro-adjusting: utilize threshold value Tf=130～140 split images to be vein Iv and background Ig two parts; If concrete operations are p (i; J)＜Tf then p (i, if j) ∈ Iv is p (i; J)＞Tf p (i, j) ∈ Ig then; Calculate vein image brightness average Bv respectively and background image brightness average Bg calculates vein background mean luminance differences Dt=Bg-Bv then; For strengthening threshold range inter-sync fine setting S1, S2 and S3 brightness, the minimum brightness of concrete operations for from Bt=min (Tz) time begins to adjust C1=C1+0.5 at every turn at Bt ∈ T, T, C2=C2+0.5, and C3=C3+0.5 is until reaching Bt >=max (Tz); Obtain maximum background luminance difference max (Dt) and light source control information Cy1, Cy2 and the Cy3 of this moment in the Bt ∈ T; Concrete operations are comparison background luminance difference max (Dt) and the background mean luminance differences Dt of being in course of adjustment; If max (Dt)＜Dt then max (Dt)=Dt; Otherwise max (Dt) remains unchanged, and notes max (Dt) corresponding light source control information Cy1, Cy2 and Cy3 simultaneously; According to Cy1, Cy2 and Cy3 light source control parameters is set, fine setting finishes; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps that strengthen are following:

S731 obtains and split image, and calculate Bv, Bg and Dt: be to utilize threshold value Tf=130～140 split images to be vein Iv and background Ig two parts said cutting apart, concrete operations be as if p (i, j)＜Tf then p (i, j) ∈ Iv, as if p (i, j)＞Tf p (i, j) ∈ Ig then; Calculate Nv in vein image brightness average

and background image brightness average formula respectively; Ng is respectively the pixel number of Iv and Ig; (i j) is the capable j row of i gray values of pixel points in the image to p; Then calculate vein background mean luminance differences Dt=Bg-Bv;

It is that the interior maximum background luminance of Bt ∈ Tz is poor that S732 calculates max (Dt): said max (Dt); Tz=125～140 are for strengthening threshold value; Concrete operations are comparison max (Dt) and the Dt of being in course of adjustment; If max (Dt)＜Dt then max (Dt)=Dt, otherwise max (Dt) remains unchanged, and notes max (Dt) corresponding light source control information Cy1, Cy2 and Cy3 simultaneously;

Does S733 judge Bt ∈ Tz? If set up then execution in step S734 synchronous micro-adjusting S1, S2 and S3 brightness, otherwise execution in step S736;

S734 synchronous micro-adjusting S1, S2, S3: the brightness of synchronous micro-adjusting grouping light source S1, S2 and S3, the concrete operations minimum brightness for from Bt=min (Tz) time begins each adjustment control C1=C1+0.5 of unit, C2=C2+0.5, C3=C3+0.5;

Whether S735 detects current checked object is human finger; Be execution in step S731 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11;

S736 is provided with S1～S3 and produces max (Dt): according to step S732, grouping light source S1～S3 is set produces background luminance difference max (Dt): corresponding light source control information Cy1, Cy2 and Cy3 are provided with light source control parameters.

Whether whether S8 is human finger: detecting current checked object is human finger; Be then downward execution in step S9; Otherwise jumping to step S11 closes light source and withdraws from all operations: prevent artificially to point extracting out fast through finger detections in place back, change artificial finger or the image fraud system forged;

Whether S9 adjusts end: judging whether that adjustment finishes, is then downward execution in step S10, and proceed adjustment otherwise jump to step S7: the condition that adjustment finishes will combine described light source control adjustment member to carry out;

S10 gathers high quality graphic: obtain high-quality, high-contrast finger venous image;

S11 closes light source, the energy-saving and cost-reducing light source life that prolongs simultaneously;

S12 withdraws from operation.

Described human finger biological characteristic detects; The dielectric constant values of human finger live body this characteristic between 12～18 during according to frequency 100～500kHz; Judge whether measured object is real human finger live body, avoid flase drop foreign matter, forgery finger or image.

The invention has the beneficial effects as follows: method is simple, and is convenient to operation, safe in utilization energy-conservation; Can obtain the finger venous image of high-quality, high-contrast automatically fast, can also get rid of non-human finger flase drop is disturbed, thus the accuracy of identification and the recognition success rate of raising subsequent treatment, the significantly security of enhanced system; The present invention is applicable to the physical characteristics collecting part in the human-body biological field of authentication, is easy to promote as early as possible.

Description of drawings

Below in conjunction with accompanying drawing the present invention is described further:

Fig. 1 is that finger venous image of the present invention obtains schematic diagram;

Fig. 2 is a light source control adjustment schematic diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is done further explain:

Embodiment 1:

Like Fig. 1, shown in 2; The false proof acquisition methods of a kind of finger venous image; Be to realize that by the comprehensive execution that finger venous image obtains, the human finger biological characteristic detects, light source control is adjusted three kinds of methods described finger venous image obtains, follow these steps to successively carry out:

The S1 system initialization, the wait human finger is put into;

Whether S2 human finger: detect finger and put into, detect human finger and put into;

S3 starts light source, and original intensity is set;

S4 obtains image, motion detection: image is carried out motion detection;

The S5 finger is in place: judge whether finger is in place;

Whether whether S6 human finger: detecting current checked object is human finger;

S7 obtains image, the Adjustment System parameter: to the discrepancy adjustment systematic parameter of tested individuality, parameter regulation means will combine described light source control adjustment member to carry out, and the light source control adjustment process is undertaken by coarse adjustment, fine tuning and three steps of enhancing successively; The concrete steps of coarse adjustment are following: carry out step S711 earlier and obtain image, calculate Bt; Carry out step S712 again and judge Bt ∈ T? Carry out step S713 again and adjust S1, S2, S3 synchronously: the light source S1 that divides into groups, S2 and S3 brightness are adjusted synchronously; Whether carrying out step S714 then, to detect current checked object be human finger; The concrete steps of fine tuning are following: carry out step S721 earlier and obtain image, calculate Bf, Bm, Br; Carry out step S722 again and judge Bf/Bm/Br ∈ Ts? Carry out step S723 adjustment S1, S2, S3 again: the light source S1 that divides into groups, S2 and S3 brightness are adjusted separately; Whether carrying out step S724 then, to detect current checked object be human finger; The concrete steps that strengthen are following: carry out step S731 earlier and obtain also split image, calculate Bv, Bg and Dt; Carry out step S732 again and calculate max (Dt); Carry out step S733 again and judge Bt ∈ Tz? Carry out step S734 synchronous micro-adjusting S1, S2, S3 again: the brightness of synchronous micro-adjusting grouping light source S1, S2 and S3; Whether carrying out step S735 again, to detect current checked object be human finger; Carrying out step S736 then is provided with S1～S3 and produces max (Dt);

Whether whether S8 is human finger: detecting current checked object is human finger;

Whether S9 adjusts end: judge whether that adjustment finishes;

S10 gathers high quality graphic;

S11 closes light source;

S12 withdraws from operation;

Wherein the most important thing is the light source control adjustment; Said finger venous image obtains confirms human finger rapid adjustment parameter in place, automatic, obtains finger venous image; Said human finger biological characteristic detects omnidistance work, can thoroughly get rid of the interference of non-human finger; Said light source control adjustment is pointed size, thickness according to individuality, and the light intensity control information is calculated in the position in finger interior joint size and joint slit, and dynamically adjustment is corresponding to the grouping light source of section before, during and after pointing, to obtain original finger venous image.

Embodiment 2:

Like Fig. 1, shown in 2, described finger venous image obtains, and light source and image capture device all are not in closed condition when having human detection; Effective in order to ensure testing process in addition, prevent that the detection starting descendant from forging finger or image deception acquisition system for extracting fast to point to change, stop immediately detecting in case find to point to withdraw, withdraw from all operations, further improve the security of system; Follow these steps to successively carry out:

The S1 system initialization, the wait human finger is put into: described initialization mainly is that initialization human finger biological characteristic detects, and frequency is set at 100～500kHz;

Whether S2 human finger: detect finger and put into; Detecting human finger puts into; Downward execution in step S3; Otherwise returning step S2 detects again: described detection finger concrete grammar is to detect to put into to detect to be the dielectric constant values of target, when detecting dielectric constant values between 12～18, promptly confirms it is that human finger is put into;

S3 starts light source, and original intensity is set: the brightness regulation scope E of said light source is provided with as follows: general human body finger detection appropriate brightness is 0.4～0.5E, and initialization brightness is 0.2～0.3E; Said light source is grouping light source S1, S2 and S3, the position correspond respectively to seized finger preceding, in and back segment; Concrete control method adopts PWM dutycycle control mode, and light source control information is respectively C1, C2 and C3, C1/C2/C3 ∈ Tc, and Tc=0～100 are the duty cycle adjustment scope;

S4 obtains image, motion detection: image is carried out motion detection, in order to accelerate detection speed; Described method for testing motion adopts the frame error method to realize; Concrete operations are that as Dpix＞Td, Td=30 is an error thresholds with the consecutive frame calculating respective pixel difference Dpix of image sequence; Pixel motion is counted U=U+1; At last according to following formula:

confirms that finger is in place, and Tm is a motion pixel proportion threshold value, and M * N is a resolution;

S5 finger is in place: judge whether finger is in place, points downward execution in step S7 in place, otherwise execution in step S6: whether condition in place is a motion pixel proportion threshold value to said judgement finger is set to Tm=0.1;

Whether whether S6 human finger: detecting current checked object is human finger; Be then to return step S5 to rejudge finger situation in place, close light source and withdraw from all operations otherwise jump to step S11: this just can effectively get rid of artificial imitation human finger or the image security threat to system;

S7 obtains image, the Adjustment System parameter: to the discrepancy adjustment systematic parameter of tested individuality, parameter regulation means will combine described light source control adjustment member to carry out;

Described light source control adjustment; According to individuality finger size, thickness, the position in finger interior joint size and joint slit is different, calculates the light intensity control information; Dynamically adjustment is corresponding to the grouping light source of section before, during and after pointing, to obtain original finger venous image; Avoided that individual finger front and back end varies in size, the problem of brightness irregularities between joint stage casing and joint, overcome because of brightness irregularities causes integral body or local detailed information and lost; The light source control adjustment process is undertaken by coarse adjustment, fine tuning and three steps of enhancing successively.

Described coarse adjustment comprises step S711, S712, S713 and S714, and grouping light source S1, S2 and S3 brightness are adjusted synchronously: described grouping light source S1, S2 and S3, the position correspond respectively to seized finger preceding, in and back segment; Concrete control method adopts PWM dutycycle control mode, and light source control information is respectively C1, C2 and C3, C1/C2/C3 ∈ Tc, and Tc=0～100 are the duty cycle adjustment scope; According to the brightness average Bt that obtains the image calculation finger venous image, adjust C1, C2 and C3 synchronously and make that

T is a coarse adjustment brightness average threshold value; Concrete method of adjustment is for as

time; T=120～150 are brightness average threshold value, if Bt＞T is C1=C1-1 then, and C2=C2-1; C3=C3-1; If Bt＜T is C1=C1+1 then, C2=C2+1, C3=C3+1; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps of coarse adjustment are following:

S711 obtains image; Calculate Bt: the brightness average of said Bt image; The practical implementation algorithm is a following formula: wherein p (i j) is the capable j row of i gray values of pixel points in the image;

Does S712 judge Bt ∈ T?: said T=120～150 are brightness average threshold value, if set up then downward execution in step S721, otherwise execution in step S713;

S713 adjusts S1, S2, S3 synchronously: the light source S1 that divides into groups, S2 and S3 brightness are adjusted synchronously; Concrete method of adjustment is that the brilliance control parameter reduces control unit, the then C1=C1-1 of the unit of control as if Bt＞T then whole reduction S1, S2 and S3 brightness; C2=C2-1, C3=C3-1; Improve S1, S2 and S3 brightness if Bt＜T is then whole, the brilliance control parameter increases a control unit, the C1=C1+1 of the unit of control then, C2=C2+1, C3=C3+1; The C1/C2/C3 of the unit of control ∈ Tc wherein, duty cycle adjustment scope Tc=0～100;

Whether S714 detects current checked object is human finger; Be execution in step S711 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11.

Described fine tuning; Comprise step S721, S722, S723 and S724; Adjust separately according to tested finger characteristics grouping light source S1, S2 and S3 brightness: said Bf, Bm and Br be respectively the finger before, in and back segment brightness of image average; The brightness of independent adjustment S1, S2 and S3 is so that Bf ∈ is Ts, Bm ∈ Ts, Br ∈ Ts, and Ts is a fine tuning brightness average threshold value.In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps of fine tuning are following: S721 obtains image; Calculate Bf, Bm, Br: before said Bf, Bm and Br are respectively finger, in and back segment brightness of image average; The practical implementation algorithm is respectively following formula:

wherein p (i j) is the capable j row of i gray values of pixel points in the image;

Does S722 judge Bf/Bm/Br ∈ Ts? Said Ts=125～140 are fine tuning mean flow rate threshold value, if set up then downward execution in step S731, otherwise execution in step S723;

S723 adjustment S1, S2, S3: the light source S1 that divides into groups, S2 and S3 brightness are adjusted separately, and concrete method of adjustment then reduces a control of S1 brightness unit, the control C1=C1-0.2 of unit for as Bf＞Ts; When BF＜Ts then improves a control of S1 brightness unit, the control C1=C1+0.2 of unit; As Bm＞Ts, then reduce a control of S2 brightness unit, the control C2=C2-0.2 of unit; When Bm＜Ts then improves a control of S2 brightness unit, the control C2=C2+0.2 of unit; As Br＞Ts, then reduce a control of S3 brightness unit, the control C3=C3-0.2 of unit; When Br＜Ts then improves a control of S3 brightness unit, the control C3=C3+0.2 of unit; The C1/C2/C3 of the unit of control ∈ Tc wherein, duty cycle adjustment scope Tc=0～100;

Whether S724 detects current checked object is human finger; Be execution in step S721 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11.

Described enhancing comprises step S731, S732, S733, S734, S735 and S736, grouping light source S1, S2 and S3 brightness synchronous micro-adjusting: utilize threshold value Tf=130～140 split images to be vein Iv and background Ig two parts; If concrete operations are p (i; J)＜Tf then p (i, if j) ∈ Iv is p (i; J)＞Tf p (i, j) ∈ Ig then; Calculate vein image brightness average Bv respectively and background image brightness average Bg calculates vein background mean luminance differences Dt=Bg-Bv then; For strengthening threshold range inter-sync fine setting S1, S2 and S3 brightness, the minimum brightness of concrete operations for from Bt=min (Tz) time begins to adjust C1=C1+0.5 at every turn at Bt ∈ T, T, C2=C2+0.5, and C3=C3+0.5 is until reaching Bt >=max (Tz); Obtain maximum background luminance difference max (Dt) and light source control information Cy1, Cy2 and the Cy3 of this moment in the Bt ∈ T; Concrete operations are comparison background luminance difference max (Dt) and the background mean luminance differences Dt of being in course of adjustment; If max (Dt)＜Dt then max (Dt)=Dt; Otherwise max (Dt) remains unchanged, and notes max (Dt) corresponding light source control information Cy1, Cy2 and Cy3 simultaneously; According to Cy1, Cy2 and Cy3 light source control parameters is set, fine setting finishes; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps that strengthen are following:

S731 obtains and split image, and calculate Bv, Bg and Dt: be to utilize threshold value Tf=130～140 split images to be vein Iv and background Ig two parts said cutting apart, concrete operations be as if p (i, j)＜Tf then p (i, j) ∈ Iv, as if p (i, j)＞Tf p (i, j) ∈ Ig then; Calculate Nv in vein image brightness average

and background image brightness average

formula respectively; Ng is respectively the pixel number of Iv and Ig; (i j) is the capable j row of i gray values of pixel points in the image to p; Then calculate vein background mean luminance differences Dt=Bg-Bv;

It is that the interior maximum background luminance of Bt ∈ Tz is poor that S732 calculates max (Dt): said max (Dt); Tz=125～140 are for strengthening threshold value; Concrete operations are comparison max (Dt) and the Dt of being in course of adjustment; If max (Dt)＜Dt then max (Dt)=Dt, otherwise max (Dt) remains unchanged, and notes max (Dt) corresponding light source control information Cy1, Cy2 and Cy3 simultaneously;

Does S733 judge Bt ∈ Tz? If set up then execution in step S734 synchronous micro-adjusting S1, S2 and S3 brightness, otherwise execution in step S736;

S734 synchronous micro-adjusting S1, S2, S3: the brightness of synchronous micro-adjusting grouping light source S1, S2 and S3, the concrete operations minimum brightness for from Bt=min (Tz) time begins each adjustment control C1=C1+0.5 of unit, C2=C2+0.5, C3=C3+0.5;

Whether S735 detects current checked object is human finger; Be execution in step S731 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11;

S736 is provided with S1～S3 and produces max (Dt): according to step S732, grouping light source S1～S3 is set produces background luminance difference max (Dt): corresponding light source control information Cy1, Cy2 and Cy3 are provided with light source control parameters.

Whether whether S8 is human finger: detecting current checked object is human finger; Be then downward execution in step S9; Otherwise jumping to step S11 closes light source and withdraws from all operations: prevent artificially to point extracting out fast through finger detections in place back, change artificial finger or the image fraud system forged;

Whether S9 adjusts end: judging whether that adjustment finishes, is then downward execution in step S10, and proceed adjustment otherwise jump to step S7: the condition that adjustment finishes will combine described light source control adjustment member to carry out;

S10 gathers high quality graphic: obtain high-quality, high-contrast finger venous image;

S11 closes light source, the energy-saving and cost-reducing light source life that prolongs simultaneously;

S12 withdraws from operation.

Embodiment 3:

Described human finger biological characteristic detects; The dielectric constant values of human finger live body this characteristic between 12～18 during according to frequency 100～500kHz; Judge whether measured object is real human finger live body, avoid flase drop foreign matter, forgery finger or image.

Claims (2)

1. false proof acquisition methods of finger venous image, it is characterized in that: described finger venous image obtains, and light source and image capture device all are not in closed condition when having human detection; Effective in order to ensure testing process in addition, prevent that the detection starting descendant from forging finger or image deception acquisition system for extracting fast to point to change, stop immediately detecting in case find to point to withdraw, withdraw from all operations, further improve the security of system; Follow these steps to successively carry out:

The S1 system initialization, the wait human finger is put into: described initialization mainly is that initialization human finger biological characteristic detects, and frequency is set at 100～500kHz;

Whether S2 human finger: detect finger and put into; Detecting human finger puts into; Downward execution in step S3; Otherwise returning step S2 detects again: described detection finger concrete grammar is to detect to put into the dielectric constant values that detects target, when detecting dielectric constant values between 12～18, promptly confirms it is that human finger is put into;

S3 starts light source, and original intensity is set: the brightness regulation scope E of said light source is provided with as follows: general human body finger detection appropriate brightness is 0.4～0.5E, and initialization brightness is 0.2～0.3E; Said light source is grouping light source S1, S2 and S3, the position correspond respectively to seized finger preceding, in and back segment; Concrete control method adopts PWM dutycycle control mode, and light source control information is respectively C1, C2 and C3, C1/C2/C3 ∈ Tc, and Tc=0～100 are the duty cycle adjustment scope;

S4 obtains image; Motion detection: image is carried out motion detection; In order to accelerate detection speed, described method for testing motion adopts the frame error method to realize, concrete operations are the consecutive frame calculating respective pixel difference Dpix with image sequence; As Dpix＞Td; Td=30 is an error thresholds, and pixel motion is counted U=U+1, and at last according to following formula:

confirms that finger is in place; Tm is a motion pixel proportion threshold value, and M * N is a resolution;

S5 finger is in place: judge whether finger is in place, points downward execution in step S7 in place, otherwise execution in step S6: whether condition in place is a motion pixel proportion threshold value to said judgement finger is set to Tm=0.1;

Whether whether S6 human finger: detecting current checked object is human finger; Be then to return step S5 to rejudge finger situation in place, close light source and withdraw from all operations otherwise jump to step S11: this just can effectively get rid of artificial imitation human finger or the image security threat to system;

S7 obtains image, the Adjustment System parameter: to the discrepancy adjustment systematic parameter of tested individuality, parameter regulation means will combine the light source control adjustment member to carry out;

Described light source control adjustment member; According to individuality finger size, thickness, the position in finger interior joint size and joint slit is different, calculates the light intensity control information; Dynamically adjustment is corresponding to the grouping light source of section before, during and after pointing, to obtain original finger venous image; Avoided that individual finger front and back end varies in size, the problem of brightness irregularities between joint stage casing and joint, overcome because of brightness irregularities causes integral body or local detailed information and lost; The light source control adjustment process is undertaken by coarse adjustment, fine tuning and three steps of enhancing successively;

Described coarse adjustment comprises step S711, S712, S713 and S714, and grouping light source S1, S2 and S3 brightness are adjusted synchronously: described grouping light source S1, S2 and S3, the position correspond respectively to seized finger preceding, in and back segment; Concrete control method adopts PWM dutycycle control mode, and light source control information is respectively C1, C2 and C3, C1/C2/C3 ∈ Tc, and Tc=0～100 are the duty cycle adjustment scope; According to the brightness average Bt that obtains the image calculation finger venous image; Adjust C1, C2 and C3 feasible

synchronously, T is a coarse adjustment brightness average threshold value; Concrete method of adjustment is for as

time; T=120～150 are brightness average threshold value, if Bt＞T is C1=C1-1 then, and C2=C2-1; C3=C3-1; If Bt＜T is C1=C1+1 then, C2=C2+1, C3=C3+1; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps of coarse adjustment are following:

S711 obtains image; Calculate Bt: the brightness average of said Bt image; The practical implementation algorithm is a following formula:

wherein p (i u) is the capable j row of i gray values of pixel points in the image;

Does S712 judge Bt ∈ T?: said T=120～150 are brightness average threshold value, if set up then downward execution in step S721, otherwise execution in step S713;

S713 adjusts S1, S2, S3 synchronously: the light source S1 that divides into groups, S2 and S3 brightness are adjusted synchronously; Concrete method of adjustment is that the brilliance control parameter reduces control unit, the then C1=C1-1 of the unit of control as if Bt＞T then whole reduction S1, S2 and S3 brightness; C2=C2-1, C3=C3-1; Improve S1, S2 and S3 brightness if Bt＜T is then whole, the brilliance control parameter increases a control unit, the C1=C1+1 of the unit of control then, C2=C2+1, C3=C3+1; The C1/C2/C3 of the unit of control ∈ Tc wherein, duty cycle adjustment scope Tc=0～100;

Whether S714 detects current checked object is human finger; Be execution in step S711 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11;

Described fine tuning; Comprise step S721, S722, S723 and S724; Adjust separately according to tested finger characteristics grouping light source S1, S2 and S3 brightness: before Bf, Bm and Br are respectively finger, in and back segment brightness of image average, the brightness of independent adjustment S1, S2 and S3 is so that Bf ∈ Ts, Bm ∈ Ts, Br ∈ Ts, Ts is a fine tuning brightness average threshold value; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps of fine tuning are following: S721 obtains image, calculates Bf, Bm, Br: before said Bf, Bm and Bm are respectively finger, in and back segment brightness of image average, the practical implementation algorithm is respectively following formula: $\mathrm{Bf}=\frac{1}{\frac{M}{3}\×N}\underset{i=1}{\overset{\frac{M}{3}}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}p(i,j),$ $\mathrm{Bm}=\frac{1}{\frac{M}{3}\×N}\underset{i=\frac{M}{3}}{\overset{\frac{2M}{3}}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}p(i,j),$ $\mathrm{Br}=\frac{1}{\frac{M}{3}\×N}\underset{i=\frac{2M}{3}}{\overset{M}{\mathrm{\Σ}}}\underset{j=1}{\overset{N}{\mathrm{\Σ}}}p(i,j),$ Wherein (i j) does p

The capable j row of i gray values of pixel points in the image;

Does S722 judge Bf/Bm/Br ∈ Ts? Said Ts=125～140 are fine tuning mean flow rate threshold value, if set up then downward execution in step S731, otherwise execution in step S723;

S723 adjustment S1, S2, S3: the light source S1 that divides into groups, S2 and S3 brightness are adjusted separately, and concrete method of adjustment then reduces a control of S1 brightness unit, the control C1=C1-0.2 of unit for as Bf＞Ts; When Bf＜Ts then improves a control of S1 brightness unit, the control C1=C1+0.2 of unit; As Bm＞Ts, then reduce a control of S2 brightness unit, the control C2=C2-0.2 of unit; When Bm＜Ts then improves a control of S2 brightness unit, the control C2=C2+0.2 of unit; As Br＞Ts, then reduce a control of S3 brightness unit, the control C3=C3-0.2 of unit; When Br＜Ts then improves a control of S3 brightness unit, the control C3=C3+0.2 of unit; The C1/C2/C3 of the unit of control ∈ Tc wherein, duty cycle adjustment scope Tc=0～100;

Whether S724 detects current checked object is human finger; Be execution in step S721 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11;

Described enhancing comprises step S731, S732, S733, S734, S735 and S736, grouping light source S1, S2 and S3 brightness synchronous micro-adjusting: utilize threshold value Tf=130～140 split images to be vein Iv and background Ig two parts; If concrete operations are p (i; J)＜Tf then p (i, if j) ∈ Iv is p (i; J)＞Tf p (i, j) ∈ Ig then; Calculate vein image brightness average Bv respectively and background image brightness average Bg calculates vein background mean luminance differences Dt=Bg-Bv then; For strengthening threshold range inter-sync fine setting S1, S2 and S3 brightness, the minimum brightness of concrete operations for from Bt=min (Tz) time begins to adjust C1=C1+0.5 at every turn at Bt ∈ T, T, C2=C2+0.5, and C3=C3+0.5 is until reaching Bt >=max (Tz); Obtain maximum background luminance difference max (Dt) and light source control information Cy1, Cy2 and the Cy3 of this moment in the Bt ∈ T; Concrete operations are comparison background luminance difference max (Dt) and the background mean luminance differences Dt of being in course of adjustment; If max (Dt)＜Dt then max (Dt)=Dt; Otherwise max (Dt) remains unchanged, and notes max (Dt) corresponding light source control information Cy1, Cy2 and Cy3 simultaneously; According to Cy1, Cy2 and Cy3 light source control parameters is set, fine setting finishes; In a single day in this process, detect human finger and leave, finish all operations at once; The concrete steps that strengthen are following:

S731 obtains and split image, and calculate Bv, Bg and Dt: be to utilize threshold value Tf=130～140 split images to be vein Iv and background Ig two parts said cutting apart, concrete operations be as if p (i, j)＜Tf then p (i, j) ∈ Iv, as if p (i, j)＞Tf p (i, j) ∈ Tg then; Calculate Nv in vein image brightness average

and background image brightness average

formula respectively; Ng is respectively the pixel number of Iv and Ig; (i j) is the capable j row of i gray values of pixel points in the image to p; Then calculate vein background mean luminance differences Dt=Bg-Bv;

It is that the interior maximum background luminance of Bt ∈ Tz is poor that S732 calculates max (Dt): said max (Dt); Tz=125～140 are for strengthening threshold value; Concrete operations are comparison max (Dt) and the Dt of being in course of adjustment; If max (Dt)＜Dt then max (Dt)=Dt, otherwise max (Dt) remains unchanged, and notes max (Dt) corresponding light source control information Cy1, Cy2 and Cy3 simultaneously;

Does S733 judge Bt ∈ Tz? If set up then execution in step S734 synchronous micro-adjusting S1, S2 and S3 brightness, otherwise execution in step S736;

S734 synchronous micro-adjusting S1, S2, S3: the brightness of synchronous micro-adjusting grouping light source S1, S2 and S3, the concrete operations minimum brightness for from Bt=min (Tz) time begins each adjustment control C1=C1+05 of unit, C2=C2+0.5, C3=C3+0.5;

Whether S735 detects current checked object is human finger; Be execution in step S731 then, close light source and withdraw from all operations: prevent artificially to extract finger fast out and changing and realize artificial finger or the image fraud system forged through pointing the back of detecting in place otherwise jump to step S11;

S736 is provided with S1～S3 and produces max (Dt): according to step S732, grouping light source S1～S3 is set produces background luminance difference max (Dt): corresponding light source control information Cy, Cy2 and Cy3 are provided with light source control parameters;

Whether whether S8 is human finger: detecting current checked object is human finger; Be then downward execution in step S9; Otherwise jumping to step S11 closes light source and withdraws from all operations: prevent artificially to point extracting out fast through finger detections in place back, change artificial finger or the image fraud system forged;

Whether S9 adjusts end: judging whether that adjustment finishes, is then downward execution in step S10, and proceed adjustment otherwise jump to step S7: the condition that adjustment finishes will combine described light source control adjustment member to carry out;

S10 gathers high quality graphic: obtain high-quality, high-contrast finger venous image;

S11 closes light source, the energy-saving and cost-reducing light source life that prolongs simultaneously;

S12 withdraws from operation.

2. the false proof acquisition methods of a kind of finger venous image according to claim 1; It is characterized in that: described human finger biological characteristic detects; The dielectric constant values of human finger live body this characteristic between 12～18 during according to frequency 100～500kHz; Judge whether measured object is real human finger live body, avoid flase drop foreign matter, forgery finger or image.

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